This invention is related to tool jigs for drilling holes and particularly to a tool jig that clamps onto the edge of a door providing a guide for the knob hole and the latch hole required for installing a lockset.
Common procedure for a builder to install a door is to order a door panel that has a standard size knob hole (hole through the door) for receiving the lockset. The hole is typically located near one long edge of the door 36 inches from the bottom edge. The hole is selected to accommoate any one of standard locksets. Installation of the lockset requires that a pattern of holes be drilled by the carpenter in the door proximal to the knob hole through which bolts are inserted to secure the lockset. The position and size of the smaller holes varies according to the lockset selected by the builder.
Alignment of the holes with the edge of the door is very critical for the sake of appearance as well as for ease of installation of the lockset. Consequently, some rather elaborate drill jigs have been disclosed that are available along with the lockset as aides in installing the doors. Such aids are particularly useful when large numbers of doors are being installed such as when erecting large tracts of residences.
The drill jigs of the prior art are typically plates holding an array of drill bushings. In a common jig, a shoulder is positioned along one edge of the plate. The plate is positioned on the door to be drilled with the shoulder abutting an edge of the door. In this manner, the holes to be drilled are aligned with the edge of the door. This arrangement is only satisfactory when all of the doors have their holes located at the same distance from the edge of the door.
In another arrangement, the jig is a channel that straddles the edge of the door with one leg (plate) of the channel on each side of the door. Each plate has an array of drill bushings, each bushing aligned with a bushing in the other plate. This arrangement is satisfactory only when all of the doors have the same thickness.
For example, U.S. Pat. No. 5,116,170 to Palmer et al discloses a drill jig for installing a lockset with a flange for attaching a C-clamp.
U.S. Pat. No. 5,479,802 to Miller discloses a method of installing a combination lock deadbolt assembly with a dial lock.
U.S. Pat. No. 5,672,034 discloses a carpenter""s locator for use with a door boring jig.
In many instances the customer requires a second knob with a dead bolt to be installed in a door. In order to install the second lockset, it is necessary to drill additional holes in the door. FIG. 1 is a cutaway prospective view (prior art) of an edge of a door 10 showing the knob hole 12 and a lock hole 14.
Cutting these two extra holes in a door for a custom job presents some complications for the workman even though the holes 12, and 14 are intended to fit an xe2x80x9coff-the-shelfxe2x80x9d lock set. One difficulty is that there are currently two xe2x80x9cstandardxe2x80x9d locksets and the difference between them is that distance between the knob hole 12 and the edge of the door may be either one of two standard sizes, i. e., 2 inches or 2xc2xd inches. Another problem according to present practice is positioning the lock hole in the center of the surface of the edge of the door with the center line of the lock hole intersecting the centerline of knob hole. The care that must be taken in accurately placing the holes adds a substantial cost to the job particularly in jobs such as apartment complexes where retrofitting a large number of doors is required.
It is an object of this invention to provide tool jig for a door lock that xe2x80x9csnaps ontoxe2x80x9d the edge of the door to provide a guide for drilling the knob hole and the lock hole where the two holes are accurately aligned with one another. It is contemplated that the tool jig will accommodate a door of any thickness within the range of thicknesses of xe2x80x9cstandard doorsxe2x80x9d presently on the market.
This invention is directed toward a pair of jaws that clamp onto the edge of a door. The clamp is first attached to the edge of the door by a spring load and then further secured by a cam which the workman turns to apply additional clamping force. A center block between the jaws has a guide hole for drilling the lock hole in the surface of the edge of the door.
The centerline of guide hole in the center block is perpendicular to the centerline of the knob hole and is positionable to permit location of the knob hole at either one of two locations depending on the style of the lock set. The center block is hingably attached to both jaws of the clamp such that the guide hole in the center block is always centered with the surface of the edge of the door.
Features, aspects and advantages of the present invention will become better understood by reference to the following description of what I presently believe to be the best mode for carrying out the invention illustrated in the accompanying drawings and further defined by appended claims.